The present invention relates generally to magnetic tape cartridges and more specifically belt-driven magnetic tape cartridges in which a magnetic tape is stored and guided along a tape path across a tape head opening, and is particularly concerned with an alignment device for such cartridges to align the tape as it passes across the tape head opening.
Belt-driven magnetic tape cartridges of the type described in U.S. Pat. No. 3,692,255 (Yon Behren) typically include various guide pins which are orthogonally mounted in a base plate. Typically, guide pins are mounted on each side of the tape head opening to align the tape as it passes across the tape head. Any misalignment of the tape or deflection from its path may cause signal distortions. This is a particular problem in current belt-driven magnetic data tapes which typically have a very high recording density and track density, and are driven at high speed across read and write heads. Even a slight vertical deflection of the tape as it travels through the tape head opening may cause problems. Thus, belt-driven magnetic tape cartridges have guide pins on each side of the tape head opening which receives the read or write head as it is pressed against the tape. Extreme tolerances are required in mounting these pins on each side of the tape head opening to ensure that they are orthogonal to the base and at a fixed height relative to one another. If either or both of the guide pins on each side of the tape head opening are tilted from the vertical or orthogonal orientation relative to the base plate, the tape will be correspondingly tilted from a horizontal path, causing alignment problems between the tape and the read/write head with corresponding signal distortions or loss. Thus, it is important that these guide pins are seated precisely in a fixed orientation to each other and relative to the base plate. The precision of this fixed orientation has been difficult to achieve in practice.